1. Field of the Invention
This invention relates to a tape cartridge containing a printing tape and a feed roller for feeding the printing tape, and a tape printing apparatus in which the tape cartridge is removably loaded and which carries out color printing on the printing tape unwound from the tape cartridge by the ink jet printing method.
2. Prior Art
Conventionally, there has not been proposed a particular tape printing apparatus of an ink jet type that prints on a tape by the ink jet printing method.
For the tape printing apparatus of the above-mentioned kind, it is contemplated that a set of feed rollers are used for winding out a printing tape from a tape cartridge and guiding the same to a printing position. The feed rollers are comprised e.g. of a drive roller and a driven roller which rotate while holding the tape therebetween for feeding the same to the proper position for printing. On the other hand, in a tape printing apparatus of a type that uses a tape cartridge containing a printing tape, it is required to feed the leading end of the tape between the drive roller and the driven roller when the tape cartridge is loaded into the body of the apparatus. That is, when the tape cartridge is loaded in the body of the apparatus, it is required that the drive roller and the driven roller be separated from each other in order to allow the leading edge of the tape to pass between them. The rollers then must be bought into contact with each other so that friction may be applied to feed the tape. When the tape cartridge is removed from the apparatus body, the drive roller and the driven roller brought into contact are required to be separated from each other once again.
In such a case, since the apparatus body is required to include means for moving either the drive roller or the driven roller in a manner interlocked with the loading/unloading operation of the tape cartridge, it is expected that the construction of the apparatus becomes complicated. Further, when the tape printing apparatus is configured such that various types of printing tapes having different widths can be used, in order to accommodate tapes of maximum width, it is required to employ drive and driven rollers having larger widths compared to the width of the smallest width tapes that can be used. However, when a small-width printing tape is fed by using drive and driven rollers of greater width, there is the potential that the dispersion of the frictional force of the rollers would prevent stable feeding of these printing tapes.
On the other hand, in a tape printing apparatus of a thermal transfer type that prints on a printing tape by the thermal transfer printing method, a tape cartridge is known which is equipped with a platen roller corresponding to a set of feed rollers. When a tape cartridge is loaded in the apparatus, the platen roller and a thermal head of the printing apparatus are opposed to each other with a tape (and an ink ribbon) positioned therebetween, and in a manner interlocked with the closing operation of a lid for a cartridge holding block, the thermal head is urged against the platen roller with the tape held therebetween. The urging of the thermal head is effected by a spring provided on the thermal head side with a desired urging or friction force.
In such a conventional construction of the printing apparatus, the urging force for providing the proper friction between the platen roller and the thermal head is obtained by the spring (urging means) provided on the apparatus. Therefore, a fixed urging force is constantly applied to the tape by the platen roller and the thermal head irrespective of the kind of a tape cartridge, i.e. the kind of a tape. As a result, depending on the kind of a tape, particularly when the tape has a large width or is made of a slippery material, the urging force becomes insufficient to obtain the proper friction to feed the tape in a stable manner. Since the printing operation and the feeding of the tape are interlocked with each other, if the tape cannot be fed in a stable manner, the quality of the print is degraded.
Further, the tape feeder of the above-mentioned kind has a set of feed rollers arranged in the vicinity of printing position, for unwinding the tape from the tape cartridge and feeding the tape to the printing position. To effect proper printing at a desired location of the tape, particularly to guide the tape accurately with respect to the position in the direction of the width of the tape, a tape guide for controlling a lateral position of the tape is arranged at a location prior to the feed rollers, and at the same time the roll of tape is provided on a core such that the roll on the core agrees with the tape in position.
In the case of such a conventional tape feeder, if the position of a roll of tape on its core is deviated in an axial direction, or the roll itself has turns deviated axially at a radial location of the roll, a portion of the tape unwound from the tape cartridge and the tape guide go out of alignment and the tape receives improper forces to produce wrinkles or undergo jamming.